Help

[jer]

I need help -- figuring out what is wrong with my car. Any input would be greatly appreicated. ( before I burn this....)
I had a new engine put in it.  This car is a 1987 Pontiac GT. It will start and run for a couple of days and than it won't run at all. Replaced core twice - replaced the distributor cap - rotor - had module tested. Tested wiring and it is ok - Still no spark coming from distriutor to number one sparkpulg.  Can any one help with information??  Thanks

[egirard]

Hi Jer,

Di you try to replace the pick-up coil?

Eric

[fiero308]

ignition modules are FAMOUS for being a problem with these cars and engines, particularly. I think part of it is simply due to the heat they have to endure. Pennocks etc is full of stories about people having brand new modules going bad and the concensus there is to use GM Delco; don't waste your time with the aftermarket stuff; they can even TEST OK then be bad later!!!  An easy enough and cheap enough fix, but a LOT of people carry a spare AND the tools to replace them on the road.

So you might want to do that simply to know 100% that it is NOT the module. Process of elimination.
Keep us posted on your findings.
 

[fiero308]

I am not an expert on the stock fiero at all; hopefully guys like Dan and Aaron and Don and Gary and Tyler and so on will chime in.  These cars are ~20 yrs old and electrical gremlins are to be expected.  Simply 'poor' connections. Once they get to that stage they tend to heat up due to resistance.... and resultant heat makess them simply oxidize that much faster till bingo! no more connection at all. But it will LOOK fine outside the plastic connector........

But what other diagnostics have you done?
does it sputter? or nothing at all?

Did it run fine at ONE point? ie do you feel 100% confident that the (distributor/ignition) timing is good?

Are the plug wires in the right places? Don't laugh. I once 'supervised' my sister while she put plug wires on her car. I sat and watched her do ONE at a TIME.... distributor to plug..... and she still got two switched! I still don't know how, either......

do you have fuel pressure? (there is a schraeder valve on the fuel rail but not sure how hard it is to get at) - be careful with it! (spraying gas around....!)

can you hear the fuel pump running? (with the key on)

have you pulled a plug or a few to check for spark?

What is happening with the gauges (if anything) when you are cranking it?  Do you see oil pressure building? Does the tach needle move? anything else?

Have you checked for codes (check engine light on?) if so, what are they?

When was the last time it DID run and what has changed since?
or if it never did run (right) what mods can you figure out were done to it. at ANY time..... and (important!) does it have ANY aftermarket stuff on it?

this stuff should help these other guys/someone come up with ideas.

[fiero308]

just re-read your first post.
No spark at all?
I think you might go thru the prev questions tho and post answers for anyone else looking.
There is an 'interlock' of sorts between the fuel pump and the oil pressure sensor and I think that is thru the ECM but not sure. Either way it won't let the car start if there is no oil pressure but I dont' really think that is what you have.

Start at the coils and work back. Also physically check grounds; you simply can't have too many and they HAVE to be in good shape. Again it sounds like something else but this is worth checking.  I suspect some connector; something that is either 100% or nothing.  The contacts inside can be quite corroded and the outside, being plastic, can look fine, so you don't know.

When it DOES run, does it run well or poorly or what is it like?

If it throws codes, can you figure out what they are? There is a way.

Again I am not really up on the fiero in stock form as I have a pretty mixed up thing myself that is still not running by the way so hopefully some of the resident experts will chime in soon.

But post everything that you have triple checked and know 105% is ok; just to help narrow it down.

gp

[fiero308]

so no spark even when you START cranking it? (oil pressure situation) Could be the sensor......

well in your searches and checking take apart each plug and connector and see how each 'spade' type connector is inside it. I had chronic problems with a 92 Astro van heater........ it would work for a long time then start acting up. I went thru 3 or 4 heater fan switches; each time it appeared that the switch was faulty.
Then, fed up and suspicious, I took a long look at the plug that goes on the switch.
ONE of the wires was "loose" so that even when the plug was firmly installed, that wire was NOT properly connected to its matching part. The poor/partial connection created heat which in turn actually melted the connector a bit more and allowed the wire to 'slip' a bit more again. Eventually there was almost NO connection.
A simple fix but it took a lot of detailed looking.

So start at the ignition and work backwards.
Check the ECM I guess, somewhere along the line but I am guessing a plug or connector somewhere in the ignition system.
Good luck and I hope you'll post your findings.
gp

[2ML67]

This is one of those problems that can test your patience. Sounds to me like its in the wiring but I could be wrong, but its hard to tell without actually looking at the car myself. I am planning on visiting with Gary soon if you like I could drop by and take a look while I am in the area. Have a few spare parts off an 87 GT that I could bring along to try and solve the problem. Dan 

[aaron88]

We are an Ottawa (Ontario, Canada) club.

Sounds to me like, you need to find your spark.  Foget about all other problems until you find that spark.  Trace back the power until you find the point where you have it.  Then check all the wires. If you have replaced all the components then it's got to be a contact problem.  That means check wires and switches.  (could be ECU)

If the engine like came on then there is an engien code to read.

Aaron

.

[dguy]

Sounds like all of the common spark-related components have been replaced, yet still nothing.  Hmmm...

When the pick-up coil was replaced, did either you or whomever was doing the work happen to note the condition of the stator & magnet on the the distributor shaft?  The magnets have been known to crack on occasion.  Here's a link which includes a photo of the stator & cracked magnet if you need a reference.

There's a two-wire harness which runs between the ignition module & the coil.  Check the condition of the connectors at each end of this harness, and check it for continuity.  Pay close attention to the locking tab at this harness's connection to the coil--it doesn't take much play there to break the circuit.

[FieroBUZZ]

Also, there is a safety switch that insures that you are in P to start the car (or brake on or whatever.  On an automatic, it is located at or near the base of the shifter.  If the bracket is bent it is possible that the car will not start.

[aaron88]

Also, there is a safety switch that insures that you are in P to start the car (or brake on or whatever.  On an automatic, it is located at or near the base of the shifter.  If the bracket is bent it is possible that the car will not start.

I might be wrong but I think this circuit works with the fuel cut off not the coil.

Let me check to be sure...my bad; it works with the starter.  If the starter will turn over this sircuit is connected.  If the starter will only turn over in P or N then the circuit is working properly.


Aaron

.

[aaron88]

Changing parts hoping that something will work isn’t really the right way to save any money while doing a repair.  Perhaps you can find someone in your local area with an automatic that is willing to lend you their ECU for a few minutes to see if the car starts.  If it doesn’t then you just saved yourself a bunch of money.

On the other hand you’re still going to spend a lot less than you would if you took your car to a shop.


Aaron

.

[fiero308]

maybe it would help to step back a bit. Try to think about something different.

did you indicate that you DID have a 'check engine' light at one point? I think that should give a code.

If not, then how about something like fusible links.  What I am getting at is maybe you have to start at the battery end and see where the power STOPS.  By the same line of reasoning, at what point (with ignition ON) DO you or DON"T you have power?
Where the power STOPS, of course, is what you are looking for.  It sounds to me like it isn't getting past a connection somewhere.

If you can't find power anywhere, maybe you need to start at the battery (and alternator?) ends..... but the battery first. That is why I suggested the fusible links. They can and do go bad but just occasionally. So worth checking.

Just ideas but easy to do. Always do the easy stuff first!!!

[fiero308]

I had a new engine put in it.  This car is a 1987 Pontiac GT. It will start and run for a couple of days and than it won't run at all. Replaced core twice - replaced the distributor cap - rotor - had module tested. Tested wiring and it is ok - Still no spark coming from distriutor to number one sparkpulg.  Can any one help with information??  Thanks

just re-reading the whole thing. You didn't say anything about codes; don't know where I got that. DID you have an engine light (check engine) at one point?

You said 'After replacing the engine, it would start and run for a couple of days' - then it hasn't run since? Is that correct?  Or was it "on and off again a few times" (intermittent prob)

Who did the swap? Someone who has done that before?

When you say you changed the "CORE" .....(twice) what do you mean by the 'core'?

When you say "tested wiring and it is OK"....... how did you test it? a voltmeter? visual check? ohm meter/continuity? (which is different) and what did you get/see? ie is there power TO the distributor? you have to verify THAT item.
Obviously if there is no power TO the distributor it has 'nothing to work with' so you have to verify that.

Hey Aaron,
I took your advice. But I couldn't find anyone around here with a ECU - not even a junk yard, But I did get my hands onto a analyzer - to which I found another part that when bad that I just replaced. So I exchanged that part for a good one. But still no spark. With what you and your friends know about this kind of car. Could it possibly be the computer now. Because when I hook up the analyzer to it now to get the codes to see what is wrong  there is nothing. I know it is not the battery took care of that. This thing doesn't flash anything. Do you have anymore ideas?
jer

What part did you find was bad?
Any info is going to help; the more the better. Even stuff that doesn't seem related; put it all down.

Questions for the other guys: would the oil pressure/fuel pump 'interlock' (auto test for oil pressure) have any bearing on the ignition? (I am thinking no).  Are there any 'sensors on the engine (think about it being replaced) that would cut out the ignition signal if they were bad?

gp

[dguy]

Questions for the other guys: would the oil pressure/fuel pump 'interlock' (auto test for oil pressure) have any bearing on the ignition? (I am thinking no). 

"No" is correct--it only affects the fuel pump.  It's not even an interlock to be honest, just a backup in case the fuel pump relay and/or the ECM's driver circuit for the relay fails.

Are there any 'sensors on the engine (think about it being replaced) that would cut out the ignition signal if they were bad?

Sensors & other components which could kill the spark include: every component of the distributor (p/u coil, magnet, pole piece, ign. module, cap, rotor, gear & roll-pin), wiring between the ign. module & coil, wiring between ECM & ign. module, coil, tach filter, ECM, cam, timing chain & gears.